The present disclosure relates generally to path diversity calculations for use in route selection.
A network typically includes multiple paths to a destination to increase the probability of reaching the destination. However, if multiple paths share a significant number of common nodes or links, then a single failure may impact all paths. Path diversity describes the number of disjoint paths between a pair of nodes in a network topology. The number of disjoint paths between the nodes depends on where and how they connect to the network. Path diversity of a network directly impacts its resilience to failure. The spread of information transfer within the network over divergent paths minimizes the impact of a single failure.
Paths between two hosts in the same autonomous system (AS) are determined by the AS's internal network infrastructure and by the intra-domain routing protocol. Paths between two nodes connected to different autonomous systems are determined not only by the network infrastructure and routing policies inside each network on the path, but also by peering connections and inter-domain routing policies. Path diversity is desirable to mitigate the impact of a failure, however, utilization of path diversity in route selection is typically limited by these routing protocols and policies.